Method of making vulcanized-rubber products.



UNITED STATES PATENT OFFICE.

RAYMOND B. PRICE, OF NEW YORK, N. Y.

METHOD OF MAKING VULCANIZED-RUBBER' PRODUCTS.

No Drawing.

ber products made from thin sheets or strips of a rubber compound.

In the description of my invention, shall refer more particularly to the practice of my art or method in connection with the production. of rubber threads, as the conditions present in such, make the application the of my improved art or method thereto'especially advantageous.

At the present time rubber threads are made by forming'a-thin sheet of the unvulcanized rubber compound, placing a fabric sheet of fine texture thereupon and rolling the same tightly about a core and upon itself, so as to have said textile presentedto both sides of the sheet of rubber. When completely wound, the roll is inclosed in outer windings of fabric, or other fibrous material, which is secured in position thereon so as to prevent the swelling, or other displacement, of the rubber during the time when the roll is subjected to the action of the vulcanizing medium. After vulcanization, the roll is unr'olled and the fabric and vulcanized rubber separated, the latter being cut into strips of the desired width. Whi e by this method the rubber can be successfully vulcanizedand the threads conveniently produced therefrom, the tendency of the rubber to swell during vulcanization develops additional internal pressure within the roll which, with the flowing of the rubber, brings the rubber into intimate en-5 gagement with the fabric and impressesthe design of the fabric upon the rubber. This condition results in the formation of threads having two sides so roughened by reason of the design of the fabric thereon, as to impart certainundesirable properties to the finished roduct, and make it difiicult to use thes'ame in those arts for which this product is in tended for use- Not. only do the roughened i surfaces increase the superficial area of each thread and thus increase the deleterious actionpf the light and air on the thread, par- Specification of Letters Patent.

Patented Sept. '7, 1915.

Application filed March 18, 1914. Serial 0. 825,508.

ticularly when under stretch, but when the threads are being woven into fabric, thetendency toward abrasion is material. With these conditions in mind, I contemplate the production of rubber products, formed from thin sheets or strips, in a manner which will impart to, or preserve in, the vulcanized sheet, opposite'surfaces which will be perfectly smooth -and free from those irregularities resulting from the impression of the design of a textile or other fibrousmaterial thereon. T

By my improved art or method, I am enabled toentirely dispense with textile ma.- terials during vulcanization and to avoid all of the objections growing out of the use of the same.

The invention consists primarily in "a ed out in the claims hereto appended.

In the practice of my invention, I use a thin sheet of unvulcanized rubber com: pound, produced by means .of a calenderor in any other desired manner, and apply to either the top or'bottom surface thereof, or to both, a thin coating or filmof a medium which even at the vulcanizing temperature, will keep the several layers of rubberdistinct, and will prevent them from forming a solid, homogeneous mass. This coated strip is then rolled upon a cylindrical core, and upon itself, forming a plurality of superimposed layers; separated by the'neutral medium. WVhen thepile is so formed, I confine the same by an external jacket so that during the vulcanization, any substantial distortion or expansion thereofis prevented. If it be found that the core, orfthe inclosing a facing of a substance, such as sheet-lead, the texture of which presents substantially no design and the said jacket maybe made of thesame, or, similar material. of forming the pile as a roll, the superim- Instead '10 jacket leavesan impression upon a portion of the strip, said core may be provided with posed layers may consist of a succession is separate sheets placed one upon the other,

the successive sheets being coated in the -manner above referred to, toprevent both the formation of a thin, continuous film of fairly uniform depth upon the surface thereof, and it does ngtpermit adjacent layers of rubber to adhere. fGlycerin, diluted with water, has al o.gi' .'en satisfactory results, while water alonejbas been used with a degree of succ'ssto domenstrate its applicability .under certain conditions tense in the practice of my method or art.

The manner of applying the material of the coating 02 lllrn to the unvulcaniz ed sheet or strip is mmaterial to my invention so long as a substantially uninterrupted or continuous surfacing of the sheet or strip results.- A suitable coating or film may be secured by submerging or dipping the sheet or strip in the material; by applying the material in comminutecl form to the surface of the sheet or strip with or without subsequent dispersion or smoothingyby applying the material with a brush; by flowing the material over the surface or in any other desired manner,

The use or" comminuted'material as a separating medium, as, for instance, powdered soapstone, is objectionable on account of a portion of it intermixing with the rubber,

thereby increasing the gravity of the compound. Powdered soapstone and various other materials may however, be used with beneficial results when suitably mixed with glycerin, for when so miuedtne tendency for thepowder to enter the rubber is avoided.

After vulcanization the separate thicknesses or plies of rubber are separated, there being no tendency of adjacent. thicknesses or plies to stick or adhere toone another. Thread, or other rubber products, made by and-in accordance with-my improved art or method, will present no roughened surfaces, so that abrasion thereof in-the loom or elsewhere, and the injurious eflects of light and-air, are minimized. 4

Having described my invention,- what I 1. method of making vulcanized rubber productsconslst-ing in superimposing upon .action of a'vulcanizing medium,

each other a "number-of layers of unvulcanized rubber compoflundhavingla coating of a tween adjacent layerawhereby adhesion of the rubber of one layer to that of its adjacent layers is vprevented, and while so coated subjecting the pile to the action of. a vulcanizing medium. 7

2. A method of making vulcanized rubber products consisting in applying a coating of a medium which is a'liquid at the vulcanizing temperature to sheeted unvulcanized rubber compound, forminga pile consisting of a number of layers of saidrubber with said medium between adj acent layers whereby the adhesion'of the rubber of one layer to that of its adjacent layers is prevented, and while so coated subjecting the pile to the action of avulcanizing medium.

6. :5. method of making vulcanized rubber products consisting in applying a coating of glycerin -to sheeted. un'vulcan ized rubber compound forming-a pile consisting of a number of layers of said rubber with said medium between adjacent layers whereby the adhesion of the rubber of one layer to that of its adjacent layers is prevented, and then subjecting the pile to the action of a vulcaniz'ing medium. I

4:. A method-of making vulcanized rubber products consisting in applying a coating of a medium which is liquid at the vulcanizing temperature to a sheet of unvulcanized rubbe r compound, rolling said sheet upon itself to form a number of superimposed layers with the said coating between adjacent layers, whereby the adhesion of the rubber of one layer tothat of its adjacent layers is prevented, confining said roll with an external jacket, and'then subjecting the roll to the A method or"- making vulcanlzed rubber products consisting in applying a'coating of glycerin to'a sheet ofunvulcanizedsrubber compound, rolling said sheet upon itselfv to form. a number of superimposed layers with the coating of glycerin between adjacent layers whereby N the adhesion of the rubber of one layertofthat of its adjacent layers is iprevented, confining said rollwith an ex ternal jacket, and then-subjecting the roll to theactionof a vulcagniaing medium.

Signed at New Y k city, county and State of New York, thisllt-h day of March, 7 d9l4. I desire to have protected by Letters Patent 1 r RAYMOND B. PRICE. Witnesses:

' JOHN J. Cesar, 

